I purchased X-Plane 10.45 a few months ago on Windows 10 using the joystick TrueMaster T160000 and programmed the button 04 for trim pitch up. Everything was working fine. When updating to V10.45 or V10.50, the pause button is added to the pitch button 04. Try this on 2 computers with the same effect. This only appears with button 04.
Also AVG Internet Security 2016 says that X-plane.exe is a kind of virus (also try on 2 computers). Have to add the exe file to exception.
Hope this help.